Suicidal Thoughts and Trajectories of Psychopathological and Behavioral Symptoms in Adolescence

This cohort study evaluates which categories and trajectories of psychopathological and behavioral symptoms are associated with suicidal thoughts among adolescence in Japan.

Main results 16 (a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (eg, 95% confidence interval).Make clear which confounders were adjusted for and why they were included   The primary caregiver answered male or female when the participant was at age 10.

annual household income
The primary caregivers answered 0 to 0.99, 1 to 1.99, 2 to 2.99, 3 to 3.99, 4 to 4.99, 5 to 5.99, 6 to 6.99, 7 to 7.99, 8 to 8.99, 9 to 9.99 or more than 10 million yen when the participant was at age 10.The responses were then grouped into 0 to 2.99, 3 to 5.99, 6 to 9.99, and more than 10 million yen when the participant was age 10.
separation from primary caregiver The primary caregivers were asked the question 'Has your child ever lived away from you (primary caregiver) for more than one year?'They then answered yes or no when the adolescents were age 10.

bereavement from family members
The primary caregivers were asked the question 'Has a family member (mother, father, siblings, and grandparents) passed away since your child was born?'They then answered yes or no when the adolescents were age 10.

mental health problems of mother/father
The primary caregivers were asked the question 'Have you experienced any physical or mental health problems that have lasted for more than one year?(This includes those that are expected to last more than one year in the future.)'If they answered yes, they indicated the specific type of problem when the adolescents were age 10.Those who indicated 'mental health problems' were considered positive.The primary caregivers answered the same questions for both themselves and their partner, and the results were labeled as either 'mental health problems of mother' or 'mental health problems of father', depending on whether the primary caregiver was the mother or the father.Here, mental health problems of mother/father reflect both the family system and the genetic perspective, which cannot be separated.

alcohol consumption of mother/father
The primary caregivers were asked the question 'How many days a week do you drink alcohol?'They then answered 'never', 'less than once a month', 'two to four times a month', 'two to three times a week', 'more than four times a week', or 'don't know/don't want to answer' when the adolescents were age 10.The answer 'don't know/don't want to answer' was considered as a missing value.
The primary caregivers answered the same questions for both themselves and their partner, and the results were labeled as either 'mental health problems of mother' or 'mental health problems of father', depending on whether the primary caregiver was the mother or the father." bullied Because children and their caregivers often report differently about children's experiences of being bullied 1,2 , we considered it a negative only if both the primary caregivers and the adolescents answered "none.Otherwise, it was considered a positive.The primary caregivers were asked the question 'In the past two months, has your child been bullied by other children?'They then answered 'several times a week', 'about once a week', 'two to three times a month', 'once or twice every two months', or 'none' when the adolescents were age 10.The adolescents were also asked the questions 'In the past two months, have you been bullied by other children in your school?' and 'In the past two months, have you been bullied by other children in your school?'They then selected 'several times a week', 'about once a week', 'two to three times a month', 'once or twice every two months', or 'none' when they were age 10.

lifetime experience of suicidal thoughts at age 12
The adolescents were asked the question 'I have ever thought I should not be alive.'They then answered 'strongly agree,' 'almost agree', 'almost disagree', and 'strongly disagree' when they were at age 12.We dichotomized the participants into those without a lifetime experience of suicidal thoughts (answered 'strongly disagree' and 'almost disagree') and those with a lifetime experience of suicidal thoughts (answered 'strongly agree' and 'almost agree').

. Estimated means of the models and the observed individual trajectories
The bold lines represent the estimated trajectories of LCGA, while the background thin lines depict the trajectories of each individual, colored by subgroup membership.For Model 3 and Model 4, the maximum VIFs from the 100 imputed data sets were displayed for each variable.
Model 1 was a univariable logistic regression analysis examining the association between each symptom trajectory and suicidal thoughts.Model 2 was a multivariable logistic regression analysis including only symptoms that were significant in Model 1. Model 3 added confounders to Model 2. Model 4 was a multivariable logistic regression analysis including symptoms that were significant in, Model 3, their interaction term, and confounders.The 'Low' subgroup was used as a reference for all symptoms.

. Additional analysis of the cross-sectional relationship between symptoms and suicidal thoughts
To examine the cross-sectional association between symptoms and suicidal thoughts, we performed logistic regression analysis using standardized CBCL subscale scores at age 16 instead of symptom trajectories in the main analysis.We fitted three models.Model 1 was a univariable logistic regression analysis for each symptom.Model 2 was a multivariable logistic regression analysis including symptoms that were significant in Model 1. Model 3 added the confounders to Model 2. Missing values were handled by multiple imputation methods.The imputation procedure included explanatory variables, outcome variables, and covariates.One hundred datasets were created and combined according to Rubin's rule.
In Model 1, all symptoms were significantly associated with suicidal thoughts.In Model

( a )
Describe all statistical methods, including those used to control for confounding 8-10 (b) Describe any methods used to examine subgroups and interactions 8-10 (c) Explain how missing data were addressed 8-10 (d) If applicable, explain how loss to follow-up was addressed 8Report numbers of individuals at each stage of study-eg numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analysed 10, 11 (b) Give reasons for non-participation at each stage 10, 11 (c) Consider use of a flow diagram S4 Descriptive data 14* (a) Give characteristics of study participants (eg demographic, clinical, social) and information on exposures and potential confounders 10, 25 (b) Indicate number of participants with missing data for each variable of interest 10, 25 (c) Summarise follow-up time (eg, average and total amount) -Outcome data 15* Report numbers of outcome events or summary measures over time 10, 25

Comparison between included and excluded participants
Values are No./total No. (%) or mean (SD).We used the chi-square test for categorical variables and the t-test for continuous variables to compare participant characteristics between those included and excluded in the study.No statistically significant differences were found between the two groups.
Values are No./total No. (%).We used the chi-square test for categorical variables to compare participant characteristics between participants between those with and without missing values in CBCL scores.No statistically significant differences were found between the two groups.eTable 2. eFigure 1.

eTable 6. The overall effect of each symptom trajectory group
The p-values were obtained by a chi-square test for the likelihood of two models: one model including only the intercept and another model including a specific symptom trajectory group as an independent variable.

The raw CBCL subscale scores for each symptom trajectory
: not applicable For Model 3, the maximum VIF in the 100 data sets of the multiple imputations for each variable was shown.